clarke



(No Model.)

. I T. A. CLARKE.

ELECTRIC BURGLAR ALARM.

N0. 594,678. Patented Nov. 30, 1897.

error;

PATENT THOMAS A. CLARKE, OF BOOTLE, ENGLAND.

ELECTRIC BURGLAR-ALARM.

SPECIFICATION forming part of Letters Patent No. 594,678, dated November 30, 1897.

Application filed January 12,1897. Serial No. 618,973. (No model.)

To otZZ whom it may concern.-

Be it known that I, THOMAS ALFRED CLARKE, licensed victualer, of 203 Derby Road, Bootle, in the county of Lancaster, England, have invented Improvements in Electric Burglar and other Alarms, of which the following is a specification.

This invention has for its object an electric alarm applicable, inter calm, as a burglaralarm, which shall also keep the burglars outside the door sufficiently long to enable the person alarmed to be put on the defensive, and also as an alarm for rousing servants in the morning, (to.

As applied for use as a burglar-alarm it consists in an electric bell or other alarm worked electrically, a battery to supply that bell, and a pair of insulated wires leading to the actual safety appliance.

Referring to the accompanying drawings, Figure 1 shows the safety appliance underneath the door of a room and the wires leading to a battery and bell, which may be inclosed in a box for convenience. Fig. 2 is an enlarged view of the safety appliance, with parts broken away for clearness; Fig. 3, a side elevation of the same, showing how contact is made; and Fig. 4, a plan thereof in its open or normal position.

In the drawings, A is the safety appliance, consisting of a wedge formed of wood or other material in two pieces B B. These pieces maybe connected at their converging points by a hinge and their opposite ends kept apart by a spring; but I have found that the metal contact-pieees, to be hereinafter described, serve the purpose,

0 O are two metal contact-plates to which the wires D D, leading to the battery, are respectively connected.

The metal contact strips before referred to, and shown best in Fig. 2, are secured to the two pieces B 13, forming the wedge, in any suitable manner and extend both along the top of the uppermost half B of the wedge and underneath the lower half 13 and are turned over the ends of the widest part of the wedge.

It will be seen that the outside strip E touches the top contact plate C, but stops short of the bottom plate 0, while the next one, E, stops short of the top plate, but is con nected to the bottom plate, and so on with each alternate strip.

F F are side contact-plates arranged one on each side to the upper and lower half, respectively, and adapted to make contact with strips G, only one of which can be seen in the drawings.

II are spikes projecting from the lower half of the wedge for fixing the appliance to the floor, as shown in Fig. 3, or in the case of a concrete floor, where the spikes cannot be used, the appliance may be shod with rubber I, having a serrated surface (shown only in Fig. 2) to prevent slipping.

The mode of action is as follows: The wedge is pressed against the floor until the spike or spikes II enter the same, as shown in Fig. 3,

the Wedge is just under the bottom of the door when such is closed, (see Fig. 1,) or, if desired, it could be placed so that the door engaging the wedge. If the door be forcibly opened, it depresses the upper half B of the wedge until the plates 0 0 come together, thereby making contact and completing the circuit. This causes the bell or other alarm device to ring loudly. If an attempt be made to force the door still farther open, the appliance acts as a wedge to prevent such opening, or if the burglar or other person attempts by means of a knife or other instrument to push the wedge away before opening the door he will, owing to the peculiar arrangement of contact-springs, cause contact to be made in whatever way he inserts the instrument. For instance, if a knife or other conductor touches any two strips marked E E contact will be made, as will be clearly understood from the drawings. If either of the two side strips be lightly pressed, contact will be made, as in this case one of the strips touches the outside top strip of the upper half of the wedge at the point e and the other a similar strip 011 the lower half of the wedge on the opposite side. hen these are pressed inward, they touch the strips G, which strips, as clearly shown in Fig. 2, are in contact with the plates 0 0'.

If the burglar endeavors to out the wires, a slight movement of the same will cause a contact by pulling the terminals 0 O together.

and in such a position that the thin end of could be opened to any desired extent before It is obvious that the wires can be brought to any desired point and ring the bell there or that two bells can be on the circuit, one rung so as to alarm the burglar, the other to alarm the watchman at a distance; also, that the circuit formed can manipulate any other electrical device useful for circumventing the burglar.

The battery is preferably a dry battery placed in a box with the bell and a coil, 850., so as to occupy as little room as possible.

As applied to other alarms besides burglaralarms the invention will be obvious without further description.

Means may be provided for using the apparatus either as a burglar-alarm or as an invalids call-bell, a device being used for changing the continuous ringing of the bell, as in the case of an alarm, to a call which rings so long as the button is being depressed.

I declare that what I claim is 1. In a burglar-alarm wedge the combination of the two portions forming the upper and lower parts of the wedge with a series of thin contact-plates formin the hinge and arranged with contacts of opposite polarity side by side and covering a greater portion of the surface of the wedge, whereby if a metal tool be used to push it away it will complete the circuit by bridging the distance between two contacts.

The combination of the wedge 13 having conducting strip G fixed thereto with the wedge B having spring-blade F of opposite polarity to the strip G and a battery X having wires D and D in electrical connection respectively with the blade F and the strip G.

3. In an electrical wedge the combination of a wedge B, B with two series of springplates E and E of opposite polarity and alternating with each other and a battery and bell having wires in electrical contact respectively with the parts E and E.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

THOMAS A. CLARKE. lVitnesses:

G. C. DvMoNn, W. 11'. Bnns'ron. 

